Will xbox live and ps3 online ever link?

no Would not matter if they did link PS3 games are not compatible with Xbox 360 games and vice verse. They could not play even on the same network any more than a PS3 game could work in a Xbox 360 console. Even if the networks were linked you would need new games developed comparable for both systems and that may not even be technologically possible. If it was they would do it to drastically reduce inventory costs for stocking so many game versions in each retail store.